a = input()
x = len(a)
d = 0
count = a.count("(")
count1 = a.count(")")
count2 = a.count("[")
count3 = a.count("]")
count4 = a.count("{")
count5 = a.count("}")
for i in range(len(a)):
    for x in range(len(a)):
        if (a[i] == "(" and a[x] == ")") or (a[i] == "[" and a[x] == "]") or (a[i] == "{" and a[x] == "}"):
            d += 1
if (d == len(a) / 2 and len(a) % 2 == 0) or (count == count1 and count2 == count3 and count4 == count5):
    print('Последовательность верная')
else:
    print('Последовательность неверная')
